Refrigerant composition



Jan. 8, 1935. R. w. DAVENPORT 5 REF HIGERANT COMPOSITION Filed Feb. 6. 193l INVENTOR. Ransom W flm/enporf A TTORNE Y.

* Patented 1.... 8, 1935 1 1,986,959

UNITED STATES PATENT OFFICE I REFRIGERANT COMPOSITION Ransom W. Davenport, Detroit, Mich., assignor to Chicago Pneumatic Tool Company, New York, N. Y., a corporation of New Jersey Application February 6, 1931, Serial No. 513,876 2 Claims. (01. 252-5) This invention relates to the transferring of nents approach each other the proportions of the heat and involves both process and working subvapor ingredients should be increased up to the stance aspects. point where the total pressure approaches one at- Among the objects are to provide improved mosphere at room temperature. The prefer! ed 5 working substances of relatively high boiling point solutions substantially in the ratio of one part of 5 and methods of employing such substances to prothe vapor or gas-component to three parts of the duce refrigeration at relatively low temperatures liquid component are as.follows: ethyl chloride but with improved efiiciency. and methylene chloride, methyl chloride and car- I have previolisly made disclosures of systems; bon tetrachloride, butane and methylene chloof refrigeration employing a working medium ride, propane and carbon tetrachloride. Other 10 comprising a liquid of relatively high boiling point high boiling componentsmay be chosen for some and an insoluble gas, which medium is expandspecific reason apart from the principle ones set ed in contact with the liquid variously to imforth above. prove the efllciency of the evaporative step of the In carrying out the invention suitable apparefrigeration process. .I have heretofore referred ratus must be provided for producing the change 15 to such a process as involving the vapor-gas prinof state in the working substance. While the imciple, the operation of which is set forth in Patprovide working substances may be used with good ent No. 1,619,196 issued to me on March 1, 1927. effect in straight pumping systems, still better re- Other engineers and inventors have disclosed vasults are secured with them when operating unrious refrigerants composed of mixtures and soder the vapor-gas principle due to the greater ef- 20 lutions of two or more components, of which reficiency of the latter. When vapor expansion into frigerants Pictets fluid serves as a. typical exam: at body of the evaporating liquid is effected as ple, but none known by me are liquid at room taught by the vapor-gas principle, a thermodytemperature and pressure. namic cycle is performed on the working sub- The present invention involves the use of a solstance consisting in alternately liquefying and 25 uble gas or vapor, instead of an insoluble gas as evaporating the liquid while alternately expanddisclosed in my aforesaid patent, and it includes ing the soluble gas into the evaporating liquid the discovery of a type of working substance and compressingit into the liquefying liquid. adapted for such use. My invention in princi- In order to illustrate the invention and the ple consists in the discovery of a refrigerant which manner of its operation, diagrammatic disclosures 30 is liquid at room temperature and pressure comof both the straight pumping and the vaporprising a solution of fluids, one of which must be gas cycl r wn n the eew p y rawa liquid at ordinary temperatures and pressures in n which: r and the other a vapor or gas at such temperatures i 1 is a i mm c View Of he conven and pressures. The vapor or gas is released from tional Straight P p ye p te 35 the liquid. solution during the evaporating step S w in S cta d of the refrigerating process and compressed back Fig. 2 is a somewhat similar diagrammatic illusinto the liquid solution during the condensing i n the v p ras principle. h step. The system may operate either on the conn 1 a y 3 0f the, liquid 8 111 71011 com- 40 ventional straight pumping cycle or in accordprising y p v d ef example 40 ance with the vapor-gas principle. In either case 5% methylene chloride and 25% ethyl chloride,

the vapor or' gas ingredient is released from the is p s in a evaporator 4 a j ed 0 '6- solution in the evaporator and forced back into duced P s through the ac i of a p p 5 solution with the liquid inthe condenser. connected to the top of ev p 4 y a P p A considerable range of components 'are avail- The refrigerant vapor drawn off by the pump will 45 able for the solution, especially as to the gas or comprise the greater portion of the ethyl chloride vapor component. The liquids most suitable for Which isav ila le in dy 11 f its re use are methylene chloride CHz Clz, boiling point r V latility and a smaller proportional part of 108 F. and carbon tetrachloride 'CCLi, boiling the methylene c lo i Th v p r under i her point 170 F. The gas or vapor ingredients may ure and p essure from t e pump n op- 50 be ethyl chloride C2H5Cl, boiling point F'., eration are discharged by pump 5 into pipe 7 methyl chloride CHaCl, boiling point 10 F., also which leads into a condenser 8 where heat is excertain hydrocarbon derivatives such as propane, tracted and the vapors are liquefied. The methylboiling point -38 F., butane, boiling point 12 F. ene chloride vapor is first to liqueiy and the ethyl 55 In general, as the boiling points of the compochloride is forced back into solution at somewhat increased pressure and lower temperature. The working substance is then returned to the body 3 in evaporator 4 inliquid form through a suitable float valve or other equivalent feeding device 9.

The illustration of the vapor-gas principle in Fig. 2 conforms to that of my aforesaid patent and is similar to the cycle described in the preceding paragraph except that a portion of the residual vapor in the condenser is forced to expand or bubble up through the body of liquid in the evaporator. As indicated in Fig. 2 evaporation of the body 3a of refrigerant, which may be methylene chloride and ethyl chloride in the ratio 3 i 1 as before, is induced by pump 5a acting through pipe 611.. The discharge of the pump is conducted by pipe 7a to condenser 8a whence leads a conduit having a feeding or expansion device 9a capable of passing both the liquid and gaseous products of the condenser in contiguity and discharging the same beneath the refrigerant body 3a. In this instance the vaporized refrigerant is not retained in the condenser until completely liquefied, as in Fig. 1, but a residual portion of it, which will be largely ethyl chloride on account of its greater: volatility, will be expanded into the body of liquid in the evaporator before or while it is at the point of being compressed into the already liquefied methylene chloride in condenser 8a.

No attempt has been made in the drawing to disclose specific apparatus for utilizing the improved refrigerant. As a matter of fact any suitable or desired types and forms of apparatus may be used. The drawing is diagrammatic and merely for the purpose of illustration.

The preferred working substances, namely ethyl chloride and methylene chloride in solution in a 1 :3 or less ratio, also methyl chloride and carbon tetrachloride in solution in the same ratio are stable and non-inflammable liquids at room temperature and pressure. The hydro-carbon solutions of butane and methylene chloride and of propane and carbon tetrachloride in the 1:3 ratio are also stable and only slightly flammable. They are readily made non-flammable by a modification of the ratio.

While the invention has been herein disclosed both in its process and working substance aspects in what are now considered to be preferred forms, it is to be understood that the invention is not confined to the specific features, components, and proportions but covers all modifications, adaptations, and relations within the scope of the appended claims.

I claim as my invention:

l. A refrigerant comprising a solution of methylene chloride with a substantial quantity of ethyl chloride, the solution having a total pressure of less than one atmosphere at room temperatures, such refrigerant being suitable for use in a refrigerating system of the closed cycle type comprising a compressor, condenser and evaporator.

2. A refrigerant comprising a solution of methylene chloride and ethyl chloride, the ethyl chloride constituting a substantial portion of but no greater than twenty-five per cent of such solution, the solution having a total pressure of less than one atmosphere at room temperatures, such refrigerant being suitable for use in a refrigerating system of the closed cycle type comprising a compressor, condenser and evaporator.

' RANSOM W. DAVENPORT. 

